These types of methods are generally known for machines with a number of position-guided elements, especially machine tools.
For machines other than machine tools, especially for production machines, other procedures are generally adopted. However numerous position-guided moving elements are present in these machines too. The movements of the individual elements are however only roughly synchronized with each other in these types of machine. This is explained in greater detail below using a plastic injection molding machine as an example.
Plastic injection molding machines have a multipart—as a rule two-part—tool form. One part of the tool is arranged statically on a chassis unit of the injection molding machine and the other part moves in relation to the chassis unit.
Once a plastic part has been injection molded, the tool mold is opened, meaning that the moving part of the tool is moved from the closed position to the open position. The injection-molded plastic part in this case is generally held in the moving part of the tool.
After the opening position is reached a handling device is moved from a rest position into a removal position, in which the handling device can remove the injection-molded plastic part from the moving tool part. Afterwards the handling device is moved back into its rest position. The moving tool part stays in its opening position in this case until the handling device has reached its rest position. Only then does the moving tool part move into its closed position again, so that the next injection molding process can begin.
The movement of the handling device and the movement of the moving tool part must obviously be coordinated with one another, so that no collisions can occur between the moving tool part and the handling device. In the prior art this is ensured by using end position switches to only enable the handling device to be moved from the rest position into the removal position once the moving tool part has reached its open position. Likewise the movement of the tool part back into its closed position is only enabled once the handling device has reached its rest position.
Although the prior art method securely guarantees that no collisions can occur, because of the movement-related delay time it often provides less than optimum dynamics and thereby an associated less than optimum machine productivity. It is thus desirable for the moving tool part and the handling device to determine the corresponding sequences of position set values, so that the moving tool part and the handling device can be moved simultaneously. In such cases, there must still be a guarantee that any collisions will be prevented.
It would be possible for a programmer to determine the supplementary position set values for the moving tool part and the handling device in such a way that the two elements are moved simultaneously and in this case the freedom from collisions is still guaranteed. However significant intellectual effort would be involved in such cases.
The object of the present invention is thus to achieve this type of simultaneous mobility of handling device and moving tool part—or in more general terms of a base element and a supplementary element—without having to make the effort of programming the two movements.